Apparatus for assembling open-ended spring retaining rings on grooved shafts, pins and the like



1957 H. ERDMANN 9 APPARATUS FOR ASSEMBLING OPEN-ENDED SPRING RETAININGRINGS ON GROOVED SHAFTS, PINS AND THE LIKE Filed May 11, 1956 5Sheets-Sheet 2 INVENTOR -JHANS [ROMAN/V ATTORNEY 1957 H. ERDMANN2,814,859

APPARATUS FOR ASSEMBLING OPEN-ENDED SPRING RETAINING RINGS ON GROOVEDSHAFTS, PINS AND THE. LIKE v 5 Sheets-Sheet 3 Filed May 11, 1956Compressed HANS ERDMA NN ATTORNEY APPARATUS FOR ASSEMBLING OPEN-ENDEDSPRING RETAINING RINGS ON GROOVED SHAFTS, PINS AND THE LIKE HansErdmann, Maplewood, N. J., assignor to Waldes Kohinoor, Inc., LongIsland City, N. Y., a corporation of New York Application May 11, 1956,Serial No. 584,229

Claims. (Cl. 29-229 This invention relates to improvements in apparatusfor assembling open-ended spring retaining rings on grooved shafts, pinsor the like, of the type disclosed in my prior application Serial No.516,073, filed June 17, 1955, and is more particularly directed to animproved version of such apparatus designed to correct shortcomingswhich become apparent in the continuing use thereof.

For example, the so-called floating mandrel of the prior apparatus, towhich the rings to be assembled are fed one at a time and thence pushedaxially therealong by the reciprocating tubular or sleeve-form plungerwhich telescopes over the mandrel, would sometimes become caught orlodged in the bore of said plunger and raised upwardly by the latter inits return (upward) movement to a position making feed movement of thenext ring to be assembled a physical impossibility. It is an importantobject of the present invention to provide, in automatic ring assemblyapparatus of the haracter under consideration, a means which is soconstructed and arranged in relation to the mandrel as positively topreclude said mandrel being caught and held in the reciprocating tubularplunger and raised by the latter on its return stroke. Moreparticularly, the invention contemplates and provides mandrel stop meanscooperatively related to said mandrel in such a way as to permit themandrel to lower against the work-piece and thereupon to return to itsnormal position in which it floats, i. e. is held by a pair ofdiametrically opposed, swinging clamp jaws in a raised positionintermediate the plunger and work-piece as in the prior apparatus, butwhich positively secures the mandrel against unintentional upwardmovement with the plunger as the latter partakes of its return stroke.Still another object of the invention is the provision of mandrel stopmeans functioning to prevent unintentional movement which additionallycombines with the aforesaid mandrel holding or clamping jaws of themandrel above its normal or floating position aforesaid in preventingturning of the mandrel under the radially asymmetrical forces likely tobe applied thereto upon the clamp jaws and/or said mandrel stop meansmoving over the usually eccentric or tapered outer edge of the ringconsequent to the latter being pushed axially along the mandrel in thecourse of an assembly operation.

Another drawback of the prior apparatus resides in its ineffectivenessin assembling the very small-size rings; that is to say, rings whosemaximum external diameter is less than the diameter of the bore of theaforesaid tubular plunger, as results in the plunger, instead ofabutting on and thereupon pushing the ring axially along the mandrel,simply moving over the same without imparting any movement thereto.Accordingly, another important object of the present invention is toinsure against such a fruitless operation through the provision of atubular plunger constructed and arranged so that its lower edge portionwhich abuts the ring has diameter rendering it capable of effectivelyabutting any size of ring capable 2,814,859 Patented Dec. 3, 1957 ofbeing received on the mandrel. More particularly, an object of theinvention is to so construct the plunger that its lower tubular end hasdiameter closely approaching that of the body portion of the mandrel,but is expansible 'so that it may enlarge to a diameter at leastequaling that of the maximum diameter of said mandrel and thecorresponding diameter of the work-piece. A more particular object ofthe invention is the provision of a tubular or sleeve-form plunger asaforesaid which is adapted to make abutting engagement with the smallestsize retaining ring which the mandrel is capable of handling,characterized in that its lower end portion has the form of an invertedtruncated cone whose smaller (lower) end is radially expansible to aninternal diameter substantially equaling the maximum diameter of themandrel and the corresponding diameter of the workpiece.

Yet another object of the invention is the provision of a means forcontrolling the operation of the air cylinder by which the tubular orsleeve-form plunger is motivated, responsively to the work-piece onwhich ring assembly is to be efiected being moved to a position directlybeneath the mandrel. More specifically, an object of the invention isthe provision of control means for said air cylinder which is energizedby movement of a work-carrying slide, either by hand or by means of afoot pedal, to a position in which it exactly aligns the Work-piece withthe mandrel, and which in turn operates to direct pressure air to theend of the air cylinder as results in the plunger partaking of itsworking stroke, whereby the apparatus is automatically placed inoperation upon the work-piece being correctly positioned with respect tothe mandrel.

The above and other objects and advantages of the improved apparatus forassembling open-ended retaining rings on grooved shafts or the likeaccording to the present invention will appear from the followingdetailed description thereof, taken with the accompanying drawings, inwhich:

Fig. 1 is a front elevation, partially in section, of the improvedapparatus for assembling open-ended retaining rings on shafts and thelike as herein proposed, the parts being shown in the respectivepositions which they assume at the end of each ring-applying operation;

Fig. 2 is a partial View of the apparatus illustrated in Fig. l, whichillustrates the additional holding action of the mandrel stop means ofthe invention on the mandrel upon opening of the mandrel clamp means;

Fig. 3 is a view similar to Fig. 2 but illustrating the mandrel stopmeans in full open or retracted position to which it is actuable by aretaining ring being moved axially along the mandrel;

Fig. 4 is a View similar to Figs. 2 and 3 but illustrating the fulllowered position of the mandrel, and the corresponding position of therelated parts at the end of an assembly operation; and

Fig. 5 is a front-to-rear section taken generally on the vertical centerline of the apparatus shown in Fig. l, which diagrammaticallyillustrates the air-cylinder control means.

Apparatus according to the present invention is generally similar intype to that disclosed in my prior application Serial No. 516,073aforesaid, in that it comprises a horizontal base 10 which mounts anupright standard 11 and a ring hopper 12, to which latter vibratorymotion is imparted by means Well known in the art. The base 10 mountswork-piece holding means, to be later described in detail, including afixture block 13 having an upwardly opening recess or socket formedtherein for the reception of a grooved shaft or similar machinepartcarrying member 15, in whose groove 16 an openended or split retainingring from the ring hopper 12 is 3 to be assembled so as to provide anartificial shaft shoulder for securing a machine part such as a plate 17mounted on the shaft against movement in one axial direction.

A stud-like mandrel 18 is normally suspended above and in spacedvertical alignment with the aforesaid shaft upon the latter beingfinally positioned, as will be explained. Illustratively, said mandrelhas a pointed upper end 18a for receiving or spearing the retainingrings to be assembled as they drop thereonto from above, a cylindricalbody portion 1811 having diameter substantially equaling that of theinternal diameter of said rings, and a frusto-conical lower end portion180 whose larger end is disposed downwardly and hence towards the shaft15, and has diameter corresponding to the diameter of the shaft end 15aover which the ring moves to the plane of the shaft groove 16. Although.diifering in detail therefrom, the preferred means for suspending orfloating the mandrel above the shaft corresponds generally to thatdisclosed in my aforesaid application and comprises a pair of oppositelyacting swingable clamp jaws 19, 20 which are normally maintained intheir horizontal or mandrel-clamping position as by means of coilsprings 21, 22, which latter are aifixed at their outer ends to thestandard 11 as by screws 23, 23a, the spring inner ends being passedthrough openings 24, 24a in the upwardly offset, free ends of said jaws19, 20. The inneror gripping-end edges of the jaws are substantiallyvertically disposed and they normally enter diametrically opposed,longitudinal slots 25a, 26a machined or otherwise formed in theperiphery of the body portion 18b of the mandrel, the grooves extendingsubstantially for the length of said body portion and terminating attheir ends in right-angled shoulders, as best seen in Fig. l. Theaforesaid mounting of the jaws 19, 20 is such that they are adapted toswing downwardly or in descending arcs about the axes of their mountingpivots 27, 28 in response to downward force applied to the upperhorizontal edges of their inner ends and, when such occurs, the mandrelis released and is free to lower on to the shaft 15.

Reference numeral 30 designates an air cylinder which is affixed to thestandard 11 above and in axial alignment with the mandrel 18. Connectedto the piston 32 of the air cylinder is a tubular or sleeve-form plunger34 whose bore throughout its major length portion is slightly largerthan the diameter of the body portion 18b of the mandrel, whereby theplunger may telescope said mandrel. Preferably, the lower end portion ofthe mandrel is provided with right-angularly related pairs ofdiametrical slots 36, 36a and 36b, 360, of which at least the slots 36,36a have width as to comfortably receive the aforesaid mandrel clampingjaws 19, 26, as is necessary to enable the plunger 34 to telescope overthe mandrel (see Figs. 3 and 4). It is also to be noted that the tubularmandrel 34 is provided at its lower end with a counterbore 37 of normalor basic diameter corresponding to that of the enlarged end 18c of themandrel and upper end 1511 of the work-piece.

The retaining rings to be assembled are fed from the aforesaid hopper 12on to a chute 38 extending downwardly at an inclination from said hopperto a level above the mandrel 18, at which the chute is provided with anopening 39 of diameter enabling the plunger 34 to lower through thechute. The chute inclination is such that the rings (generallydesignated 40) moving on to the upper end thereof tend to slidedownwardly therealong by gravity, finally to drop through the opening 39on to the mandrel 18 when free to partake of this movement. To providefor orderly one-at-a-time feed of the rings to the mandrel,ring-stop-and-feed means are provided, such illustratively comprising alever 41 disposed above the chute 38 and being pivoted intermediate itsends to the upright 11, as by a pin or pivot 42, for limited rockingmovement. A spring 43 operative between one (the upper) end of the leverand the standard 11 normally biases said lever in counterclockwisedirection to a position in which a stop pin 44 depending from the underface of said lever end is lifted from an opening 45 provided therefor inthe chute, in which position of the lever a depending pin 46 on itsother (lower) end is lowered into a second lower-level opening 47 in thechute, generally as shown. To provide for rocking movement of the lever41 against the bias of the aforesaid spring 43 a rod 48 is connected tothe end of the lever opposite that to which the spring connects, saidrod extending upwardly through an offset projection or lug 49 aflixed tothe upper end of the plunger 34 and terminating immediately above saidprojection in an enlarged head 50. The relation of said projection 49and said head 50 is such that when the plunger 34 is in its full raisedposition it exerts slight upward pull on the rod 46 as it swings thelever 41 in clockwise direction by an amount sufiicient to raise the pin46 from its opening 47 and, conversely, to lower the pin 44 into itsopening 45. Such results in the lowermost ring 40 of the series thereofdisposed on the chute being held by the pin 44 against further movementdown the chute. Also, as the pin 46 pulls away from the hole 47, a ringpreviously held by said pin (as in Figs. 2-4) is free to move downwardlyalong the chute to the opening 39 and thereupon to drop on to themandrel 18. Upon the projection 49 lowering from the rod head 50consequent to the initial movement of the plunger 34 on its downward orworking stroke, lever 41 is rocked counterclockwise by the spring 43,such raising pin 44 and lowering pin 46 into its opening 47, thereby tolower the series of rings on the chute a distance of one ring and tohold said ring series until the rod 48 is again raised by the projection49 upon the plunger returning to substantially its full raised orstarting position. Thus it will be seen that the retaining rings to beassembled can only feed one at a time on to the mandrel 18, and thatsuch ring feed is timed to occur upon the plunger having completed orsubstantially completed its return or upward stroke.

In the operation of apparatus as described above, such of courseassuming the parts are in their position shown in Fig. l, and furtherthat a ring to be assembled (designated R) has dropped through opening39 of the chute 38 to the mandrel 18 consequent to the preceding returnstroke of the plunger 32 and is resting on the upper edges of themandrel clamping jaws 19, 2t), lowering movement of said plunger is ofcourse initiated by supplying air to the upper end of the cylinder 30.Such results in said plunger partaking of its working stroke, during thecourse of which the lower end of the plunger, consequent to its tubularor sleeve-form construction, moves over the upper pointed end 18a of themandrel, whereupon its lower edge engages the ring R. Upon suchengagement being made, further lowering movement of the plunger effectslowering of the mandrel against the force of the clamping jaw springs21, 22 until, finally, the mandrel engages against the upper end of thework-piece (shaft) 15. When this occurs, further lowering of the plungerforces the ring R axially along the cylindrical body portion 18b of themandrel, the swinging motion permitted the clamping jaws enabling thejaws to recede as the ring moves past same, all as shown in Fig. 2.Further lowering movement of the plunger forces the ring axially overthe lower frusto-conical end portion 18c of the mandrel, resulting inthe ring being spread to an internal diameter corresponding to that ofthe work piece 15. Final lowering movement of the plunger moves the ringover the end of the work-piece to the plane of its groove 16, whereuponthe ring snaps into said groove (Fig. 4), thus to complete thering-assembly operation.

Assuming air to be supplied to the opposite end of the air cylinder uponring assembly having been effected as aforesaid, the plunger 34 beginsits upward or return stroke. During the course thereof, the clamp jaws19,

which have moved back into the slots a, 26a of the mandrel upon the ringhaving moved downwardly past the same, are free to close on said mandreland raise it from the work-piece to its floating position illustrated inFig. 1 which they normally tend to do under the urge of their springs21, 22. However, with the prior apparatus as disclosed in my aforesaidapplication Serial No. 516,073, the mandrel 18 sometimes became caughtor lodged within the bore of the lowered plunger 34, with the resultthat it was raised substantially above its aforesaid normal position, asdetermined by the action of clamp jaws, by the return movement of theplunger. When such occurred, ring feed to the mandrel became impossibleas in such case the upper end of the mandrel projects through the chuteopening 39 and blocks passage of the rings therethrough.

According to the present invention, this undesirable feature of theprior apparatus is corrected through the provision of mandrel stop meansnow to be described. Referring first to Fig. 1, it will be seen that theupright 11 mounts on its front face intermediate the work-piece mountingmeans 13 and the chuck jaws 19, 20 a pair of plate brackets 52, 53 whichform aligned horizontal slideways in which are received a pair ofoppositely disposed blades 54, 55 which are normally biased to theirinnermost positions by means of springs 56, 57 operative between theirouter ends and fixed points on the aforesaid brackets. At least theinner (adjacent) edges of said blades are thinned so that they mayfreely enter the aforesaid oppositely disposed slots 25a, 26a of themandrel,

and said inner ends are moreover inclined upward1y-outwardly away fromtheir bottom edge lines which lie on a common horizontal line, asindicated at 54a, 550, Fig. 3. As also seen in Fig. 1, said commonbottom-edge line of the blades 54, 55 is spaced from the commonupper-edge line of the clamp jaws 19, 20 (upon the latter being in theirnormal horizontal position) a distance equaling the axial length of themandrel slots 25a, 26a.

Thus, in the normal or floating position of the mandrel 18, the innerends of the mandrel stop blades 54, 55 project into the mandrel slots25a, 26a and engage along their common bottom edge line against thelower rightangled ends or shoulders of said mandrel slots.Correspondingly, the inner ends of the clamp jaws 19, 20 also extendinto said mandrel slots and bear along their common top edge lineagainst the right-angled, upper end shoulders of said mandrel slots.Hence the aforesaid arrangement of clamp jaws and stop blades is suchthat said clamp jaws normally secure the mandrel in its normal raisedposition and said blades positively hold the mandrel against beingraised past said normal position, as when it is caught or lodged withinthe plunger 34 and tends to move upwardly with said plunger.

It will be understood, of course, that consequent to their slidingmounting and the inclination of their upper inner edges 54a, 55a theaforesaid mandrel stop blades 54, 55 interpose no interference to thelowering movement of the ring R as the plunger 34 telescopes over themandrel. Instead, as best shown in Fig. 3, the ring merely earns theblades outwardly against the bias of the springs 56, 57 as it is pushedpast same. Upon the ring passing said blades 54, 55 the latter againclose on the mandrel so that they normally assist the clamp jaws 19, 20in holding the mandrel against turning. In addition to this normalassist action, said blades 54, 55 also serve the important function ofsecuring the mandrel against turning movement about its axis, whichsometimes occurs consequent to the radially asymmetrical forces likelyto be applied thereto by the opening clamp jaws 19, 20 when a taperedring is being pushed past said jaws, as in Fig. 2. Thus, the blades 54,55 take over the function of the clamp jaws 19, 20 in holding themandrel against rotation when said clamp jaws are either unable to actin this capacity or are actually applying forces to the mandrel tendingto turn it.

Another objectionable feature of the prior apparatus was found to bepresent in its inability effectively to assern'ble the very small sizesof rings, i. e. rings having external diameter less than the borediameter of the lower end of the plunger 34. According to the presentinvention, however, this objectionable feature is overcome by formingthe lower end portion 34a of the plunger 34 to inverted frusto-conicalshape, and with a smaller-end diameter which is slightly less than thelarger-end diameter of the conical upper portion 18a of the mandrel.Thus, upon the plunger partaking of its working stroke, its lower edgefirst engages on the conical surface 18a of the mandrel, and, consequentto said edge having smaller internal diameter than that of the conicalmandrel portion, the plunger is rendered eifective to act on thesmallest size of ring which the mandrel can take, and of course it alsoexercises a slight gripping action on the mandrel as tends to lift it toits normal raised position.

Since the lower end of the plunger 34 must expand to a diameter as greatas that of the lower large-diameter end of the mandrel (andcorrespondingly of the workpiece) in order for the plunger to movedownwardly over said latter parts, as in Fig. 4, it is a further featureof the invention that said inverted frusto-conical end 34a of theplunger is made radially elastic or expansible, preferably both throughthe provision of the aforesaid diametrically opposed slots 36-36(2,inclusive, which are of course cut through said lower frusto-conical endof the plunger, and also by thinning the walls making up said lower endportion 34a of the plunger, as indicated at 58, 59, compared to the wallproper of the plunger body.

Thus, consequent to the reduced diameter of the lower end edge of theplunger, as compared to that of the bore above said edge, the plunger iscapable of engaging with and exerting push on any size of retaining ringwhich the mandrel can handle, even to the smallest sizes of such ring.At the same time, the lower end of the plunger is suificiently elasticor flexible that it is capable of expanding to a diameter enabling it totelescope over the larger diameter-end of the mandrel and thecorresponding diameter of work-piece.

According to a further practical feature of the present apparatus, meansare provided for initiating travel of the plunger 32 on its workingstroke under control of the workpiece (shaft) 15 being positioned belowand in exact alignment with the mandrel 18. For this purpose the fixtureblock 13 which directly mounts the work-piece is itself a component of aslide assembly 60 which is adapted to slide in a slideway member 61afiixed to the base 10 with its center line coinciding with thefront-to-rear vertical center line of the apparatus. Also disposed onthe base 10 and rearwardly of the slideway is a normally open controlswitch 62 of a type that when engaged by the slideway is adapted toclose the circuit of a solenoid 63 whose armature 64 is connected bysuitable linkages 65 with the operating lever 66 of a four-way valve 67in the compressed air line to the air cylinder 30. With the valve 67 inits position illustrated, compressed air is being admitted to the lowerend of the air cylinder, thus maintaining the plunger 34 in raisedposition. However, when the slide assembly 60 is moved inwardly, eitherby hand or by foot-operated lever means, for example, to a position suchthat it engages and closes switch 62, pull on the valve-operating lever66 by the solenoid 63 causes movement of the valve to a second positionin which it supplies compressed air to the upper end of the air cylinder30, resulting in the piston 32 and plunger 34 being actuated throughoutits working stroke. Any suitable means for effecting return movement ofthe valve 67 to its illustrated position upon the ring-assemblyoperation having been completed may be employed. It will of course beunderstood that the movement of the slide assembly 60 and/or position ofthe switch 62 are such that the switch is closed at the instant that thework-piece is positioned inexact vertical alignment with the mandrel 18.

. While the above described apparatus has been found in practice tofulfill the objectives therefor as explained in the foregoing in ableand effective manner, it will be understood many changes could be madein carrying out the above constructions without departing from the scopeof the invention, and it is intended that all matter contained in theabove description or shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

I claim:

1. Apparatus for assembling open-ended retaining rings on grooved shaftsand the like comprising, in combination, means for supporting a groovedshaft in upright position and with its grooved end disposed upwardly, aring spreading mandrel disposed above and coaxial with said shaft forreceiving a ring to be assembled and for spreading it during itsmovement therealong to the grooved end of the shaft, a verticallyreciprocable tubular plunger normally disposed above and coaxial withthe mandrel and adapted during its lowering movement to telescope overthe mandrel and shaft end, thereby both to push a ring received on theupper end of the mandrel axially therealong to the groove of said shaftand to spread the ring over said shaft end, said mandrel havingdiametrically opposed longitudinal slots in its periphery,

the lower ends of which terminate in abrupt shoulders,

releasable mandrel-clamping means for holding said mandrel in a normalposition raised from said shaft end and being also effective normally tosecure the mandrel against turning movement comprising oppositely actingpivoted arms spring-biased for swinging movement to an active positionin which their adjacent inner ends extend into said mandred slots andgrippingly engage the mandrel body, said arms being swingable to aninactive position in which their said inner ends are without said slotsresponsively to said plunger in its lowering movement acting on said armends through a ring being pushed along the mandrel, said plunger beingprovided with diametrically opposed arm-receiving slots which enablesaid arms to return substantially to their said active position withinsaid mandrel slots upon the ring lowering past said arms, and meansnormally coacting with said mandrel slots and their lower-end shouldersfor preventing upward movement of the mandrel past its normal raisedposition and being also operative, during the interval that the saidinner ends of the mandrelclamping arms are without the mandrel slots asaforesaid, to secure the mandrel against turning movement about its axisunder asymmetrical forces applied thereto by the ring being pushedtherealong, said last means being retractible from the mandrel slotsresponsively to engagement therewith of the ring being pushed along saidmandrel.

2. Apparatus for assembling open-ended retainingi rings on groovedshafts substantially as setforth in claim working stroke said plunger isenabled to act and exert push on the smallest size'ring receivable bythe mandrel and on its return stroke it exercises a gripping action onthe mandrel tending to raise it to its normal raised position.

3. Apparatus for assembling open-ended retaining rings on grooved shaftssubstantially as set forth in claim 1, wherein'said last means comprisesoppositely acting blades mounted for sliding'movement toward and awayfrom said mandrel, said blades being spring-biased towards said mandrelto an active position in which their inner ends extend into the mandrelslots and engage against the lower-end slot shoulders thereby todetermine the uppermost raised position of the mandrel.

4. Apparatus for assembling open-ended retaining rings on grooved shaftssubstantially as set forth in claim 1, wherein said plunger is radiallyexpansible and has an effective inner diameter whenunstressed which isslightly less than the diameter of the mandrel body whereby the plungeron its return stroke tends to raise said mandrel, and said last meanscomprises oppositely acting blades mounted for sliding movement towardand away from said mandrel and being spring-biased to an active positionin which their inner ends extend into the mandrel slots and engageagainst the lower-end slot shoulders thereby to prevent upward movementof the mandrel past its normal raised position as aforesaid. I

5. Apparatus for assembling open-ended retaining rings on grooved shaftssubstantially as set forth in claim 1, wherein said mandrel slots alsoterminate at their upper ends in abrupt shoulders, and wherein saidlast-named means comprises oppositely acting blades mounted for slidingmovement toward and away from said mandrel and are spring-biased to anormal position in which their inner ends extend into the mandrel slots,the length of said mandrel slots and the spacing between said pivotedarms and said sliding blades being such that in the normal raisedposition of the mandrel the upper edges of the pivoted arms abut theupper-end slot shoulders and the lower edges of the blades engage thelowerend slot shoulders.

References Cited in the file of this patent UNITED STATES PATENTS979,438 Courtney Dec. 27, 1910 2,755,538 Kirsch July 24, 1956 2,773,409Huyett Dec. 11, 1956 2,775,283 Greer Dec. 25, 1956

